Page 469 - Environmental Nanotechnology Applications and Impacts of Nanomaterials

446 Potential Impacts of Nanomaterials

offer greater surface area than their bulk counterparts, allowing for
improved performance in established applications. Quantum dots (QDs)
are semiconductors that display narrow fluorescence or absorption bands
due to the quantum constraints imposed on electrons by the finite size
of the material. Applications of QDs include medical imaging and sen-
sors. Some nanomaterials are intentionally dispensed into the envi-
ronment, such as zerovalent iron nanoparticles, which have been applied
at more than 20 sites for the in situ remediation of groundwater con-
taminated with chlorinated solvents. Commercial applications of such
inorganic nanomaterials currently or will soon include nano-engineered
titania particles for sunscreens and paints, silica nanoparticles as solid
lubricants, and other reagents for groundwater remediation.
Organic nanomaterials, such as fullerenes and carbon nanotubes, are
also being produced in increasing amounts. For example, buckminster-
) is being used in applications ranging from cosmetics to
fullerene (C 60
drug delivery vectors to semiconductors while carbon nanotubes com-
posites are used in tires. Frontier Carbon built a plant to mass produce
C 60 on the scale of tons per year [9]. The economy of fullerene produc-
tion indicates that fullerene-containing products will soon become widely
available. Although C is relatively insoluble in water, it does not pre-
60
cipitate completely when coming into contact with the aquatic envi-
ronment. C 60 can form stable nanoscale suspended aggregates (nC ),
60
whose concentration can reach up to 100 mg/L [4, 10]. Fullerols (hydrox-
ylated fullerenes) are highly photosensitive and generate ROS that
may be used for bio-oxidations [11]. Both fullerols and carboxyfullerenes
can be used in medical applications as drugs or for diagnostic drug
delivery [12]. These derivatized molecules are more soluble in water
than their parent fullerene, implying greater potential interaction with
organisms.
In the environmental technology industry alone, nanotechnologies
hold great promise for reducing waste production, cleaning up industrial
contamination, providing potable water, and improving the efficacy of
energy production and use. On the other hand, the environment will be
increasingly prone to suffer pollution from nanomaterials in consumer
products such as sunscreens, detergents, and cosmetics, as well from
accidental releases during production, transportation, and disposal
operations. The manufacture, use, and disposal of engineered nanoma-
terials are not currently regulated by any government, although the US
House Scientific Committee has prioritized legislation of nanotechnol-
ogy research [13–15]. There has also been movement toward including
environmental and health issues in the European Union and Japanese
research budgets for nanotechnology. The current European budget for
research in these areas is approximately $7.5 million, a much smaller
share of their total nanotechnology research budget.